1. Field of the Invention
The present invention relates to a fuel cell resin frame equipped membrane electrode assembly including a membrane assembly and a resin frame member. The membrane electrode assembly includes an anode, a cathode, and a solid polymer electrolyte membrane interposed between the anode and the cathode. The resin frame member is provided around the solid polymer electrolyte membrane.
2. Description of the Related Art
In general, a solid polymer electrolyte fuel cell employs a solid polymer electrolyte membrane. The solid polymer electrolyte membrane is a polymer ion exchange membrane. In the fuel cell, the solid polymer electrolyte membrane is interposed between an anode and a cathode to form a membrane electrode assembly (MEA). Each of the anode and the cathode includes electrode catalyst as an electrode catalyst layer and porous carbon as a gas diffusion layer. The membrane electrode assembly is sandwiched between separators (bipolar plates) to form a fuel cell. In use of the fuel cell, generally, a predetermined number of power generation cells are stacked together to form a fuel cell stack, e.g., mounted in a vehicle.
In some cases, in the membrane electrode assembly, the surface size of one of gas diffusion layers is smaller than the surface size of the solid polymer electrolyte membrane, and the surface size of the other gas diffusion layer is the same as the surface size of the solid polymer electrolyte membrane, e.g., as a stepped-type MEA. In such cases, frame equipped MEAs, i.e., MEAs equipped with resin frame members are adopted for reducing the amount of relatively expensive material used for the solid polymer electrolyte membrane and protecting the solid polymer electrolyte member in a form of a thin film having low strength.
For example, a membrane electrode assembly disclosed in Japanese Laid-Open Patent Publication No. 2009-514144 (PCT) (hereinafter referred to as conventional technique) is known. In the membrane electrode assembly, as shown in FIG. 13, on one surface of an ion exchange membrane 1, a catalyst layer 2a and a gas diffusion layer 3a having a surface size smaller than that of the ion exchange membrane 1 are provided.
A surface la which is not supported by the gas diffusion layer 3a is included in the one surface of the ion exchanger membrane 1. A catalyst layer 2b and a gas diffusion layer 3b are provided over the entire other surface of the ion exchange membrane 1. The ion exchanger membrane 1 has a seal member 4 for sealing the edge and the surface la of the gas diffusion layers 3a, 3b. 